The investigators intend to study children and adolescents from 8 to 18 years suffering from diabetes mellitus type 1 for more than one year. The patients will undergo a detailed clinical examination for anthropometric data, blood pressure, blood and urine. Motor and sensory nerve conduction velocity will be examined by electrical stimulation using surface patch electrodes. The nerves to be examined are the nervus tibialis anterior, nervus medianus and nervus peroneus.